For actual performance, abilities and character it has to be Sisko - he's the only one of the "captains" who really developed over the run of his series imo.
For Acting it's got to be Picard
For fun it's got to be Kirk
Sisko was imo the most rounded and fleshed out of the Captains, with the most development over his run.
Picard was sort of the Serious guy you could rely on when you had a problem, but suffered from preachy storylines and NG had a bad case of "reset and restart" in terms of stories (it was rare for things in one episode to have any influence on later ones most of the time).
Kirk was all too reliant on luck a lot of the time, and fairly flat in the TV series.
Janeway, stiff and basically willing sacrifice crew to keep to the rules a lot of the time.
Archer - meh
Oddly enough I prefer TOS and even Enterprise to NG.